Reed relays having aiding coils to couple highly inductive operating coils to reed blades



Jan. 27, 1970 H. w. VAN HUSEN 3,492,613

REED RELAYS HAVING AIDING COILS TO COUPLE HIGHLY INDUCTIVE OPERATING COILS TO REED BLADES Filed Aug. 14, 1967 INVENTOR. HENDRIK W. VAN HUSEN ATTY.

United States Patent 3,492,613 REED RELAYS HAVING AIDING COILS TO COUPLE HIGHLY INDUCTIVE OPERATING COILS TO REED BLADES Hendrik W. van Husen, Glen Ellyn, Ill., assignor to Automatic Electric Laboratories, Inc., a corporation of Delaware Filed Aug. 14, 1967, Ser. No. 660,481 Int. Cl. H01h 1/66', 51/00 US. Cl. 335151 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to reed relays and more particularly to reed relays of the type having the operating coil wound about a core adjacent the reed switches thereof.

Normally, in the use of reed relay devices, the in ductance of the relay is kept to a minimum; however, in some cases, notably in certain communications applications, for example, as in the case of a batter feed device of a telephone system, such as disclosed in US. Patent 3,293,368, a high inductance condition is desirable.

While a reed relay of the type using a coil wound iron core as the operating medium is well suited for these purposes, the low reluctance path of the relatively closed magnetic circuit of the relay and the leakage currents which sometimes exist when all current should have ceased, often cause the reed contacts of a normally open version of the relay, after having been operated to a closed condition, to remain closed when they should be released.

It has been observed in a reed relay of the abovementioned type that upon the energization or deenergization of the operating coil, because of the respective increase and decrease in current in the coil, a resultant change in the magnetic field of the relay occurs. It is the utilization of this change in field upon the deenergization of the operating coil to remedy the holding situation described above, as well as the use of this" change generally, to modify the close and release characteristics of the reed switch contacts of such a reed relay, upon which the present invention is based.

SUMMARY OF THE INVENTION I Accordingly, this invention provides a reed relay of the type described which avoids the problem of the reed switch contacts thereof, once operated to a closed condition from remaining in said condition upon the deenergization of the operatnig coil.

ICC

The invention also provides a reed relay of the above type in which, by means of the utilization of the change in the magnetic field occurring in the relay upon the energization or deenergization of the operating coil, the operating characteristics may be modified.

The invention further provide a reed relay of the above type which may be advantageously used as a battery-feed relay of a telephone, or similar system.

Briefly, a preferred embodiment of the reed relay according to the invention comprises a U-shaped iron core, the ends of which are adjacent a reed switch or switches. In addition to the usual operating coil wound about the core, there is also wound thereabout a second winding. A tertiary portion of this second winding is wound, in a predetermined sense; i.e., either in aiding or opposing relation to the operating winding, about the reed switch or switches. Upon the energization or deenergization of the operating coil, a short surge of voltage is induced in the second winding to apply a resulting momentary magnetic flux through the tertiary portion thereof, to the reed switch or switches, which in turn, depending upon the manner in which the second winding is wound about both the switches and core, will either act to boost the action of the operating coil or opposed the action thereof, thus causing the reeds either to open or to close more rapidly or more slowly as the case may be.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention, and its organization and construction may be had by referring to the description below in conjunction with the accompanying drawings, of which:

FIG. 1 is a schematic representation of a reed relay according tothe invention, which serves to illustrate, in a simple manner, the principle upon which the invention is based;

FIG. 2 is a perspective view of a preferred, practical embodiment of a reed relay according to the invention which may be used as a battery feed relay of a telephone system; and

FIG. 3 is also a perspective view of the reed relay of FIG. 2 with single turn windings being substituted for the coils shown in FIG. 2, so as to better described the construction of the relay.

DETAILED DESCRIPTION Referring to FIG. 1 of the drawings, a prefered embodiment of the reed relay according to the invention comprises a U-shaped iron core 10 having bight portion 11 and legs 12 and 13. Adjacent the ends 14 and 15 of legs 12 and 13, respectively, is located a reed switch device 16. The reed switch device is of the usual type including a pair of magnetic reed blades 17 and 18, which when subjected to a magnetic field, close to complete an external circuit (not shown) connected thereto. The blades, as can be seen, are sealed into a closed, insulated chamber 19, normally constructed of a vitreous material. The U-shaped core shown in the drawings is not essential to the invention; however, it is preferred because it provides a better concentration of the magnetic operating field at the reed switch than does a conventional parallel, straight-line core.

An operating coil 20 is wound about the bight portion of iron core 10, which when energized by means of battery 21 upon depression of switch 22, serves to produce, through iron core 10, the necessary magnetic field to operate the reed switch 16. -An additional coil 23 which serves as a magnetic coupling means is wound about both the reed switch 16 and the iron core 10, shown here on the bight portion 11, such that upon the energization or deenergization of coil 20', a change in the magnetic field of core results, which in turn, causes a voltage to b induced into portion 24 of the coil 23. This induced voltage causes current to fiow in coil 23 which produces a momentary magnetic field at the tertiary portion 25 there of, wound about the reed switch 16. The magnetic energy from this momentary field or flux, depending on the sense in which coil 23 is wound about the iron core and the reed switch with respect to the manner in which operating coil is wound about the core, either aids or opposes the operating magnetic field created upon the energization of operating coil 20. For example, in the case of a normally open reed switch device, if coil 23 is wound about iron core 10 and reed switch 16 in such a manner as to assist the operating magnetic field, the induced momentary magnetic field will cause the reed switch 16 to close more quickly and positively. Furthermore, upon the deenergization of the operating Winding 20, i.e., upon the opening of switch 22, an opposing magnetic field is produced in the manner explained above, which tends to quickly spring the reed blades apart. Thus, through the addition of this extra coil, acting as a magnetic coupling means, a normally open reed switch device which might tend to remain closed upon the deenergization of the operating coil can be made to be opened promptly and efliciently. Furthermore, through the effective use of this magnetic coupling means, the speed of operation of the device may be modified as desired for specific applications.

FIG. 2 illustrates an embodiment of a relay according to the invention designed primarily for use as a battery feed relay of a telephone system. As is Well known in the telephony art, a battery feed relay supplies talking battery to the subscriber station of the telephone exchange. In performing this task the relay should maintain the talking or voice frequency on the telephone line, and the noise, if any, in the battery. To do this well the windings of the battery feed relay should be balanced electrically, thus reducing pick up of extraneous voltages to which a telephone line might be exposed. The relay of course may be used in other applications as desired.

The embodiment as illustrated in FIG. 2 comprises a U-shaped, laminated iron core 50, best seen in FIG. 3 of the drawings. As will be noted, the outer laminations of each of the legs 51 and 52 of the core extend beyond the other laminations thereof to provide support for the reed switch device 53, in its specially designed holder 54 in the magnetic operating field of the relay.

In the relay of FIG. 2, three coils 56, 57 and 58 are each wound on a respective bobbin 59, 60 and 61, the latter two being fabricated so as to slide over the legs of the U-shaped core into a mounted position on bight portion 62. Bobbin 59, which is supported between the core' legs 51 and 52, has a pair of protrusions 63 and 64 which extend in opposite directions as shown. Protrusion 64 has mounted thereon terminals 69 which are used to connect the reed switch via holder 54 to an external circuit (not shown). Bobbins 59, 60 and 61 are preferably constructed of a molded plastic.

Each of the bobbins 57 and 58 has a pair of legs 65, 66 and 67, 68, respectively, extending downward and having terminals such as 69 mounted thereon. Through these terminals, coils 56, 57, 58 are interconnected by means of wires such as 70 in the manner illustrated in FIG. 3. by single windings 80, 81 and 82.

As explained above, when used as a battery feed device it is essential that windings of the relay be balanced so as not to pick up noise and distortion on the telephone line in which the relay is being used. To achieve this necessary balance operating coil 80 is wound partially about both legs 51 and 52 of the iron core. With each portion of the operating coil, there is, as shown in FIG. 3, concentrically wound, a portion of the secondary winding 81.

The tertiary portion thereof, 82 is wound separately about the reed switch device 53. Thus, to relate FIGS. 2 and 3, winding 56 of FIG. 2 corresponds to tertiary portion 82 of winding 81 of FIG. 3. Approximately one-half of secondary winding 81 and one-half of operating winding are concentrically wound about leg 52 of the core in FIG. 3 and correspond to coil 57 of FIG. 2, and likewise approximately one-half of secondary winding 81 and onehalf of operating winding 80 are concentrically wound about the core leg 51 of FIG. 3 and correspond to coil 58 of FIG. 2. The coils 56, 57 and 58 of FIG. 2 have been superimposed in dotted lines in FIG. 3 to further describe their relation to windings 80 and 81 of FIG. 3.

The entire relay when completely assembled is placed in a housing 55 shown in dotted lines in FIG. 2. The housing preferably is constructed of a metallic material for magnetic shielding purposes, but could be of a difiFerent material if desired. As can be seen in FIG. 2, the housing 55 includes a cover portion having tabs such as 92 with apertures therethrough for mounting the entire relay structure to a support surface, such as printed circuit card (not shown). A base plate portion (not shown) is fitted to cover portion 90 to completely enclose the relay structure.

The operation of the relay of FIGS. 2 and 3 is like that of the relay of FIG. 1. Upon the energization of the operating coil 80 by depressing switch 98, battery 99 supplies current which passes through coil 80, here in a direction from point 1 to 8 thereof. As the current passes through Winding 80, a current is induced in winding 81 in a direction from point 9 to 14 thereof. The current in winding 81 creates a momentary magnetic field in tertiary portion 82 about reed switch 53 which, because of the manner in which the winding 81 is wound about the reed switch and core, assists the magnetic operating field, and causes the reed blades to close positively and rapidly. Upon the deenergization of the operating winding 80, caused by the release of switch 98, another change in field results. This change in field again induces a current in winding 81, but in a direction opposite to the one induced upon the energization of the operating coil; i.e., in a direction from points 14 to 9 thereof. The magnetic field resulting from induced current will oppose the operating magnetic field and therefore assist the reed blades in opening.

Thus, the instant invention provides a relay of the high inductance type, using a coil wound iron core as the operating medium, which not only is free from the drawbacks frequently present with such a relay, but in addition, is capable of having the operation thereof modified so as to suit the particular environment and function in which, and for which, it might be used.

What is claimed is:

1. A relay'comprising:

a core structure having a pair of separated poles,

a magnetic switching element bridging said poles,

an operating winding wound on said core structure,

said magnetic switching element conducting a sufiicient portion of the magnetic flux resulting from energization of said operating winding to cause operation of the switching element,

an additional coil electromagnetically coupled to said core structure and to said magnetic switching element, magnetic energy being coupled from said core to said switching element to modify the amount of magnetic flux through said switching element according to the sense of said coil in response to changing current in said operating winding, whereby the operating characteristic of said switching element is modified by the electromagnetic coupling of said additional coil.

2. A relay according to claim 1 wherein said magnetic switching element is a reed switch having blades of mag netic material, said blades having free ends overlapping to form a pair of contacts, and said additional coil being closely magnetically coupled to said contacts.

3. A relay according to claim 2 wherein said core structure is substantially U-shaped said additional coil having a first portion encircling said contacts of said switching element and a second portion wound on said cover structure, said first and second portions being interconnected in a series closed circuit.

4. A relay according to claim 3 wherein said core is symmetrical, said core comprising a pair of legs joined by a bight, said operating winding comprising two sets of similar interconnected operating coils, each winding having an equal number of said operating coils on each of said legs, said operating coils of each winding being References Cited UNITED STATES PATENTS 5/1961 Kamps 335151 X 3/1965 Mishelevich et a1. 335154 10 B'ERNARD A. GILHEANY, Primary Examiner R. N. ENVALL, JR., Assistant Examiner US. Cl. X.R.

connected in a series aiding arrangement with Successive- 15 335177 

